1. Field of the Invention
The present invention generally relates to a rotary cutting machine and, more particularly, to the rotary cutting machine for cutting a flat cardboard plate made up of a plurality of laminated corrugated cardboards.
2. Description of the Prior Art
The rotary cutting machine of the kind referred to above is well known in the art. The known rotary cutting machine includes a support table on which a flat cardboard plate is intermittently transported in a direction longitudinally of the support table, and a rotary cutter having a cutting blade movable in a direction transverse to the support table, that is, in a direction widthwise of the flat cardboard plate for cutting the flat cardboard plate into a plurality of corrugated cardboard blocks of a predetermined length while the flat cardboard plate then transported along the support surface is held still. The cutting blade used in the rotary cutter in the known cutting machine generally in the form of a circular saw having a multiplicity of saw teeth that are alternately offset with respect to side faces of the circular saw.
In this known rotary cutting machine, it has been found that as the diameter of the rotary cutting blade increase, the saw teeth of the rotary cutting blade tend to deform considerably in a direction laterally of the plane of rotation of the rotary cutter. Thus, the use of the rotary cutting blade of a relatively great diameter results in not only reduction of the cutting accuracy expressed in terms of the kerf of a predetermined width, but also a rocking motion of the rotary cutter while the latter is rotating. This in turn results in increase of the kerf with a correspondingly large amount of chips consequently cut from the flat cardboard plate, accompanied by a consequent reduction of the yield of the corrugated cardboard blocks cut from the flat cardboard plate.
On the other hand, if the rotary cutting blade of a reduced diameter is employed in an attempt to eliminate the above discussed problems, the maximum thickness of the flat cardboard plate that can be cut is limited. By way of example, if the rotary cutter having the rotary cutting blade of 560 mm in diameter is disposed below the support table with an outer peripheral portion of the rotary cutting blade protruding upwardly from the support table for cutting the flat cardboard plate, the thickness of the support table becomes one of elements that limits the maximum thickness of the flat cardboard plate that can be cut and, therefore, a maximum of about 140 mm in thickness of the flat cardboard plate is available for cutting with the known rotary cutter. If the rotary cutter is disposed above the support table, the thickness of the support table does no longer constitute a cause of reduction of the maximum thickness of the flat cardboard plate that can be cut, but the maximum thickness of the flat cardboard plate that can be cut is still limited to about 170 mm.